Novel approach to analytical modelling of steady-state heat transfer from the exterior of TEFC induction motors (original) (raw)
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Thermal Science, 2017
Compared to a number of other existing correlations for heat transfer, the empirical correlations for forced convection from a short horizontal cylinder in axial air-flows usually do not involve the effects of changes in air-flow velocity and/or air-flow turbulence. Therefore, a common analysis of the heat transfer by using only one energy balance equation for entire outer surface of a solid is considered insufficient for induction motor applications because it fails to include aforementioned effects. This paper presents a novel, empirically-based methodology to estimate approximately the values of air-flow velocities and turbulence factors, that is, velocity profiles and turbulence factor models for stationary horizontal cylinders with and without fins (frame and two end-shields) in axial air-flows. These velocity profiles and turbulence factor models can then be used in analytical modelling of steady-state heat transfer from the exterior of totally enclosed fan-cooled induction mo...
Thermal Analysis of TEFC Induction Motors
In order to manufacture smaller and more efficient electric motors an accurate prediction of the motor thermal performances at the design stage is a necessity. In addition, the thermal performance often needs to be analyzed when a motor is used in a different way to which it was originally designed for. An important example is the use of variable speed drives with induction motors designed for mains supply. These thermal requirements mean than accurate and reliable motor thermal models are required by the designers. In this paper the thermal behavior of Total Enclosed Fan Cooled (TEFC) induction motors are investigated using a commercially available software package called Motor-CAD ® . This software has been used to develop thermal models for five industrial induction motors from the same series (rated powers of 4 kW -7.5 kW -15 kW -30 kW -55 kW, 4 poles, 380 V, 50 Hz). The models produced have been experimentally verified. In particular, for each motor, the results obtained using the software's default parameters have been compared with solutions obtained using tuned parameters obtained through thermal tests. The analysis and the results reported in the paper allow us to give some general guidelines useful for obtaining accurate thermal models of TEFC induction motors. In particular we give advice on developing models for use in the calculation of motor derating when changing from mains to inverter supplies.
IEEE Transactions on Energy Conversion, 2009
For a totally enclosed fan-cooled induction machine, two methods of numerical analysis are compared with measurements. The first numerical method is based on computational fluid dynamics (CFDs) and the second one uses a thermal equivalent circuit (TEC). For the analysis based on CFD, a 3-D induction machine including housing is modeled. The numeric solution of the flow equations is determined for stationary temperature distributions. For the TEC, a discretized one-and-a-half-dimensional model of the induction machine is considered. With the TEC model, stationary and transient operating conditions can be simulated. Measurement results are determined by iron-copper-nickel sensors embedded in the stator winding and the housing, as well as by an IR sensor for measuring the rotor temperature. With these measurement signals, stationary and transient operating conditions can be analyzed. For stationary operating conditions, additionally, the housing temperatures are determined by an IR camera. The investigated simulation and measurement methods reveal different local and global temperatures, and thus, only certain aspects and characteristics of the obtained temperatures can be compared. Nevertheless, certain conclusions can be drawn from comparing these aspects considering the actual restrictions of each of the applied methods. Index Terms-Fluid flow, induction machines, simulation, temperature.
Thermal Analysis of an Induction Motor by Hybrid Modeling of a Thermal Equivalent Circuit and CFD
2014
The constant pressure over manufacturers for the production of smaller, more efficient and less expensive motors motivates a thermal analysis simultaneous to an electromagnetic project. In this context, this paper presents a Thermal Network model of a monofasic induction motor with permanent capacitor used in domestic applications. The transient solution and modeling are made with Modelica programing language. The heat transfer convective coefficients are determined by computacional fluid dynamics modeling. Hence, this paper presents a hybrid model which provides fast and accurate results in steady or transient states and for different flow states: turbulent forced convection and natural convection. The model has been validated with experimental data.
Impact of the Fan Design and Rotational Direction on the Thermal Characteristics of Induction Motors
2018 XIII International Conference on Electrical Machines (ICEM), 2018
This document is the author's post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it. Φ Abstract-Low manufacturing cost and high reliability make the induction machine suitable for different constant and variable speed applications. For machines operating in hazardous environments, the fully enclosed type is used, with limited access to the stator and rotor. Indirect air cooling method is usually employed with fins casing and an attached fan. Thus, the fan design is crucial as being the only resource to remove heat away from the machine. A poor thermal management of the electrical machine can lead to a machine failure and reduce the machine lifespan. Some machines are operating for bi-directional operation, which means the performance of the machine should be reviewed under both conditions. This paper focus on the impact of the fan cooling on the thermal profile of a 5.5 kW induction machine under bidirectional operation. Comparative studies using CFD simulations have been carried out to identify the effect of different fan types when operating at particular conditions. The performed work provides an understanding of the air flow under bi-directional operation, which notes the importance of the fan design and rotational direction in induction machines.
Thermal analysis of electric motors in engine cooling fan systems
SAE Technical …, 2001
Thermal study of electric engine cooling (EEC) motors is conducted using 3D CFD and conjugate heat transfer analysis. Complicated airflow fields and temperature distribution inside the motor are obtained. Predicted temperatures agree well with experimental results.
Flow and Thermal Analysis of a Two Pole TETV Motor using CFD
GRD Journals , 2020
Ventilation studies in Motors with complicated geometry are generally carried out with analytical methods during design stage. However, analytical methods do not provide comprehensive information of flow and temperature fields inside the motor at a system level. Therefore, CFD techniques are being extensively employed by motor manufacturers to analyze motor cooling systems. In the present work, Flow & Heat transfer analysis of Totally Enclosed Tube Ventilated (TETV) motor was carried out using ANSYS CFX. The complete fluid domain was modelled and heat loss data was defined on heat generating components. The ventilation flow circuit and calculated temperatures on critical components have been studied and end winding temperatures are compared with physical test data. The CFD results were within 5% of the tested data.
Thermal analysis of a three-phase induction motor based on motor-CAD, flux2D, and matlab
Indonesian Journal of Electrical Engineering and Computer Science, 2019
This paper adopted a thermal network method (TNM) based on Motor-CAD software, and Matlab/SIMULINK, with finite element method (FEM) based on Flux2D software to perform a thermal analysis of a totally enclosed fan-cooled (TEFC), squirrel cage, three-phase induction motor. The thermal analysis is achieved based on a precise knowledge of the test motor geometry, materials, and heat sources (losses). The estimation of heat distribution inside the test motor by this three software is done successfully with a good agreement between its results. The proposed triple-software methodology for this work can be adopted from the motor designer instead of using an experimental test based on a real motor.